There’s a distinct chill in the air today. It could be the return of autumn, or it could be that Ed Balls is speaking about what he’d do as Chancellor, were Labour to win in 2015.

There may be a rabbit or two yet to be dragged from the Shadow Chancellor’s hat, but the pre-briefing gives the gist of his speech. George Osborne’s limits on child benefit would be extended for two more years. Well-off pensioners would lose Winter Fuel Allowance. Ministers’ pay would be cut by 5 per cent, and only increased again when the government hit its deficit target.

The proposals are eye-catching (though, to Balls’ evident frustration on the Today Programme, not sufficiently eye-catching to prevent his speech being trumped by news of Labour’s paralysis on English Home Rule). As a long-standing supporter of the TaxPayers’ Alliance, there’s little in those three ideas that I would fault – the problem is that this isn’t the real Ed Balls. This is him in drag, mimicking the get-up of deficit hawks for a day in the desperate hope of changing his reputation. But under the new outfit, the reality is still the same.

Balls knows that the public still don’t trust him or his party to deal responsibly with the economy. Last week’s Ashcroft National Poll found that 62 per cent of swing voters worry that Labour “might spend or borrow more than the country can afford”. A third of Labour voters agree. 64 per cent of swing voters agree that “Labour have not yet learned the right lessons from what went wrong during their time in government, and cannot yet be trusted to run the country again”.

For a start, voters’ suspicions about Labour are ingrained. Simply saying that you’d extend the child benefit ‘freeze’ does not look very convincing when your party has attacked it for four years – the Shadow Chief Secretary to the Treasury, Chris Leslie, who does not twitch a limb unless Balls pulls his strings, even criticised the policy during this year’s Budget debate. Are voters to believe what Balls declares on one day, or what his party has said and done consistently for years?

Today’s announcements barely dent the wider picture of Labour’s plans for a return to fiscal disaster. Only last week the IFS confirmed that Labour’s plans remain more flabby than Osborne’s – their carefully worded pledges would still allow them to borrow £28.3 billion more each year.

Yesterday, polling for the BBC’s Sunday Politics found that a huge 85 per cent of Labour candidates for the General Election think the last government’s level of spending was “about right”. A further 10 per cent thought it was too low.

Today, a timely report from the CPS reminds us that the Opposition are also threatening to introduce numerous more tax hikes – from increasing taxes on businesses to introducing new taxes on housing. The report estimates the combined impact of the main ten policies would be that by 2019 GDP would be £25 billion lower, and there would be 306,500 fewer jobs.

Then there’s the awkward fact that Balls has already promised to spend the money from just one of his new taxes at least eleven times over – splashing the same cash over and over again on every shiny goody he and his colleagues can imagine.

So voters have a choice of which Shadow Chancellor to believe in. The one on stage today, dressed as a stern, responsible guardian of the taxpayer, singing ditties about “difficult decisions”, or the one that will emerge from his dressing room five minutes after the act is over, gripping the public credit card tightly in his hand and heading straight out to spend, spend, spend. After 13 years of Labour profligacy, and four years of them in Opposition denying they did anything wrong, today’s one-off performance won’t do anything to dispel the electorate’s doubts.